Kantar* have just said that grocery sales were up 20.6% in March to their highest ever level, peaking 16th - 19th March. From our analysis of shopper's receipts submitted to us as part of cashback claims, we can see that they were up much earlier than usual that week, probably to "avoid the crowds" or just get there when items are in stock. This happened again the week after, when the restrictions were increased as the chart below illustrates: